Polyunsaturated fatty acids in the food chain in Europe.

Intakes of partially hydrogenated fish oil and animal fats have declined and those of palm, soybean, sunflower, and rapeseed oils have increased in northern Europe in the past 30 y. Soybean and rapeseed oils are currently the most plentiful liquid vegetable oils and both have desirable ratios of n-6 to n-3 fatty acids. However, soybean and rapeseed oils are commonly partially hydrogenated for use in commercial frying to decrease susceptibility to oxidative degradation. This process leads to selective losses of alpha-linolenic acid (18:3n-3). Intake of linoleic acid (18:2n-6) has risen in many northern European countries. In the United Kingdom, intakes have increased from approximately 10 g/d in the late 1970s to approximately 15 g/d in the 1990s. The intake of alpha-linolenic acid is estimated to be approximately 1-2 g/d but varies with the type of culinary oil used. There are few reliable estimates of the intake of long-chain n-3 fatty acids, but those are generally approximately 0.1-0.5 g/d. The increased use of intensive, cereal-based livestock production systems has resulted in a lower proportion of n-3 fatty acids in meat compared with traditional extensive production systems. Overall, there has been a shift in the balance between n-6 and n-3 fatty acids over the past 30 y. This shift is reflected in the declining concentrations of docosahexaenoic acid and rising concentrations of linoleic acid in breast milk.